The　faying　surfaces　of　spot　welds　were　assumed　to　be　sharp　notch　with　two　slope　planes,　finite　element　software　ANSYS　was　used　to　model　two-spot　tension-shear　spot-welded　samples　of　different　nugget　diameter,　the　notch　local　elasto-plastic　stress　and　stain　in　the　periphery　of　the　nuggets　for　samples　under　loading　of　different　amplitude　and　different　mean　value　were　analyzed,　and　the　nonlinear　behaviour　of　the　material　was　also　taken　into　account.　Three　kinds　of　local　stress-strain　life　prediction　methods　were　applied　to　calculate　the　crack　initiation　life　in　terms　of　the　notch　local　stress　and　strain　result,　including　Morrow　modified　Manson-Coffin　equation,　Smith-Watson-Topper　equation,　and　maximum　principal　strain　equation,　and　three　groups　of　prediction　results　were　discussed　and　analyzed　separately.　Results　showed　that　within　low　cycle　fatigue　regime,　crack　initiation　sites　of　samples　of　different　nugget　size　differs,　Morrow　modified　Manson-Coffin　equation　suits　better　for　the　crack　initiation　life　prediction　of　spot　welds,　while　the　other　two　methods　having　very　diversified　results.